Double-break vacuum relay



June 21, 1966 s, EGG Rs ETAL 3,257,524

DOUBLE-BREAK VACUUM RELAY Filed Nov. 22, 1963 INVENTOR. FREDERICK S. EGGERS WILLIAM D. ESCOBA R BY United States Patent 3,257,524 DOUBLE-BREAK VACUUM RELAY Frederick S. Eggers and William D. Escobar, San Jose,

Calif., assignors to Jennings Radio Manufacturing Corporation, San Jose, Calif., a corporation of Delaware Filed Nov. 22, 1963, Ser. No. 325,667 8 Claims. (Cl. 200-87) This invention relates to electromagnetic relays and more particularly to improvements in vacuum relays.

One of the important objects of the present invention 'is to simplify the construction of such relays to reduce the cost of jigging and production.

Another object of the invention is the provision of a method of improving the radio frequency properties of transfer relays. A still further object of the invention is the provision of a transfer relay possessing vibration, shock, life and reliability characteristics not heretofore achieved in transfer relays of equivalent design.

A still further object of the invention is the provision of a transfer relay capable of operation through at least 25 million operations.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be apparent from the following description and the drawings.

It is to be understood however that the invention is not limited by the description and the drawings, as it may be embodied in various forms within the scope of the appended claims.

Broadly considered, the transfer relay of the invention comprises an hermetically sealed envelope into which extend a pair of axially aligned conductive members providing spaced contact points within the envelope and terminal leads outside the envelope. A movable contact assembly is provided within the envelope movable to selectively make or break a circuit between the spaced contact points, and means are provided on the envelope to actuate the movable contact. Means are also provided within the envelope to limit movement of the movable contact upon actuation to break a circuit through the relay.

Referring to the drawings:

FIG. 1 is a vertical cross sectional view taken in the plane indicated by the line 1-1 in FIG. 2.

FIG. 2 is a horizontal sectional View of the relay taken in the plane indicated by the line 22 of FIG. 1.

FIG. 3 is a fragmentary view illustrating the movable contact in one of its extreme positions opposite to that shown in FIG. 2.

FIG. 4 is a fragmentary elevational view taken in the direction indicated by the arrow 4 in FIG. 1.

In a well known transfer relay of the single-pole singlethrow type it has been customary to mount the movable contact bridge plate so that the bridge plate remains in mechanical and electrical contact with one of the spaced contact points and is merely engaged or disengaged from the other single contact point to make or break a circuit therebetween. In such a construction it has been customary to provide a single stop member within the envelope against which one end of the movable bridge plate may abut, and to provide a slot in one of the contact points Within which the other end of the bridge plate is caught. In such construction the slotted contact point functions as a stop or fulcrum for one end of the bridge plate. Experience has taught that this construction is unreliable and costly because it is diificult to maintain the required tolerances to provide uniformity of characteristics between mass-produced relays.

Accordingly, the present improvement over this conventional relay structure is directed to the elimination of the relationship between the slotted contact point and the cooperatively related movable contact or bridge plate,

3,257,524 Patented June 21, 1966 and the substitution of a novel contact arrangement which improves the vibration, shock and life characteristics of the relay while materially reducing production costs, thus enabling placement of a more reliable relay into the hands of consumers at a substantially decreased cost.

In more specific terms, the invention comprises a transfer relay including an electromagnetic actuating assembly 2 having a housing 3, a core member 4, and a coil 6 energized through terminals 7 and 8 to provide a magnetic circuit to which a pivoted armature 9 is responsive.

Mounted on the housing 3 is a dielectric envelope portion 12 hermetically joined to the housing by a copper sealing flange structure 13 as shown. The dielectric envelope portion is preferably fabricated from high dielectric strength glass, is symmetrical in shape and supports a pair of axially aligned conductive members 14 and 16 which respectively provide spaced contact points 17 and 18 within the envelope and terminal leads 19 and 21 outside the envelope. As shown best in FIGS. 2, 3 and 4, the conductive members 14 and 16 are diametrically opposed and hermetically sealed in the glass envelope portion.

In order to make or break a circuit through the conductive members 14 and 16, it is necessary that the spaced contact points 17 and 18 be bridged by the movable conductive contact or bridge plate designated generally by the numeral 22. The bridge plate preferably comprises a horizontally disposed U-shaped portion 23 the arms 24 of which are pivotally supported on 'a centrally disposed dielectric stern structure 26 resiliently mounted on the armature by means of a bracket 27 and stud shaft 28. The bridge plate also includes oppositely disposed transversely extending lug portions 29 lying in the same plane but offset somewhat from the central axis of the relay as shown best in FIG. 3. It will thus be seen that as the armature is pivoted in response to energization of the coil, the bridge plate will move away from or disengage the contact points 17 and 18, thus breaking a circuit therebetween, while de-energization of th' coil results in pivotal movement of the armature in the opposite direction by coil spring 31 interposed between the armature and the housing. Under the impetus of the spring the bridge plate will be brought into bridging engagement with the contact points 17 and 18, thus making a circuit therebetween.

Because of the pivotal relation between the bridge plate and the centrally disposed stem 26, it will be obvious that the contact lugs 29 on the contact will come to rest against the contact points 17 and 18 irrespective of failure in production to meet specifications such as the axial alignment of members 14 and 16. In other words, the cooperative relationship between contact points 17 and 18 and the bridge plate, together with dielectric stem portion 26, is such that irrespective of manufacturing irregularities, the bridge plate will nevertheless always make physical contact with contact points 17 and 18.

Conversely, whenthe coil is energized to break a circuit through the relay, because of the pivotal relationship between the bridge plate and dielectric stem portion 26, one or the other of the bridge plate lugs 29 is apt to pull away from its associated contact point before the other. In the conventional transfer relay, heretofore described, in which one of the lugs normally continuously remains in contact with one of the contact points this would not be detrimental, except that it would provide only a single gap between the opposite contact points, thus limiting the voltage that can be imposed on the relay. In the present structure, means are provided to insure that both lugs 29- will be disengaged from their associated contact points upon energization of the coil, thus providing a double gap and thereby increasing the applicable voltage limit by about twice that capable of being imposed on a single-gap relay. Such means comprise a pair of substantially parallel or juxtaposed spaced stop members 32, preferably in the nature of dielectric posts extending transversely toward and associated with opposite ends of the bridge plate. This construction is shown best in FIGS. 2 and 3.

It will thus be seen that when the coil is energized and the bridge plate moves away from the contact points 17 and 18, because of the pivotal relationship of the bridge plate with the stem 26, if one of the bridge platelugs moves away from its associated contact point before the other, it will merely abut the associated end of dielectric post 32. In these circumstances the end of the post will now function as a fulcrum for the bridge plate so that continued transverse movement of the stem will elfect disengagement of the other lug and move it into engagement with its associated post 32. This position of the bridge plate 22 is illustrated in FIG. 3, which, when compared with FIG. 1, reveals that in the disengaged position illustrated in FIG. 3 the movable contact is resiliently held against the stops 3-2. This cooperative relationship results in a decided increase of resistance of the device to vertically and transversely imposed shock and vibration.

1 Testshave indicated that a life characteristic of up to forty-five million operations may reasonably be expected and that the relay as described above is capable of withstanding vibration up to Gs from 55 to 2000 cycles per second. -Shock tests conducted acwrding to Mil- STD-202 B, reveal that units designed as described above would easily withstand 60 Gs for approximately eleven milliseconds.

We claim:

1. A relay comprising an envelope, a pair of axially aligned conductive members extending into the envelope to provide terminal leads outside the envelope and spaced contact points within the envelope, movable contact means within the envelope including a conductive bridge plate movable transversely with respect to said axially aligned pair of conductive members into and out of engagement with the spaced contact points to selectively make or break a circuit therethrough, and abutment means within the envelope apart from said movable contact means and against which the bridge plate impinges upon disengagement thereof from both spaced contact points.

2. A relay comprising an envelope, a pair of axially aligned conductive members extending into the envelope to provide terminal leads outside the envelope and spaced other free end normally disposed spaced from the associated end of the bridge plate.

3. The combination according to claim 2 in which the envelope and the transversely extending posts are dielectrics.

4. The combination according to claim 1, in which the movable contact means comprises an armature movably mounted within the envelope, a support stern on the armature having a free end disposed adjacent the spaced fixed contact points, and the bridge plate is pivotally disposed on the stern adjacent the free end thereof.

5. The combination according to claim 2, in which the bridge plate includes a U-shaped mounting portion with oppositely disposed transversely extending lug portions lying in a comm-0n plane.

6. The combination according to claim 5, in which the movable contact means includes a dielectric rod portion, the U-shaped mounting portion of the bridge plate being pivotally supported on the rod, and the lug portions of the bridge plate are offset from the axis of the rod.

7. A relay comprising an envelope, a pair of axially aligned conductive members extending into the envelope to provide terminal leads outside the envelope and spaced contact points within the envelope, a movable contact assembly within the envelope including an armature, a

stem having one end resiliently mounted on the armature and its other free end disposed adjacent the spaced contact points, a conductive contact bridge plate pivotally supported adjacent the free end of the stem and movable thereby into and out of bridging relation with the spaced contact points to selectively make or break a circuit.

therethrough, and a pair of transversely extending juxtaposed posts each having a free endspaced from the associated end of the bridge plate to provide spaced abutments against which the associated ends of the bridge plate impinge when the bridge plate is move-d out of bridging relation with the spaced contact points.

8. In a vacuum relay having an envelope including a dielectric portion, spaced contact points within the envelope connected to terminal leads outside the envelope and a bridge plate'within the envelope movable into and out of engagement with both spaced contact points, the improvement comp-rising a pair of juxtaposed abutments within the envelope arranged to insure a double gap between the bridge plate and the spaced contact points when the bridge plate is moved to break a circuit through the relay.

References Cited by the Examiner UNITED STATES PATENTS 5/1961 Jennings 200-144 10/ 1964 Gratzmuller ZOO-166 

1. A RELAY COMPRISING AN ENVELOPE, A PAIR OF AXIALLY ALIGNED CONDUCTIVE MEMBERS EXTENDING INTO THE ENVELOPE TO PROVIDE TERMINAL LEADS OUTSIDE THE ENVELOPE AND SPACED CONTACT POINTS WITHIN THE ENVELOPE, MOVABLE CONTACT MEANS WITHIN THE ENVELOPE INCLUDING A CONDUCTIVE BRIDGE PLATE MOVABLE TRANSVERSELY WITH RESPECT TO SAID AXIALLY ALIGNED PAIR OF CONDUCTIVE MEMBERS INTO AND OUT OF ENGAGEMENT WITH THE SPACED CONTACT POINTS TO SELECTIVELY MAKE OR BREAK 